Display screen or portion thereof with transitional graphical user interface



FIG. 1 is the first image in a sequence for a display screen or portionthereof with transitional graphical user interface showing our newdesign;

FIG. 2 is the second image thereof;

FIG. 3 is the third image thereof;

FIG. 4 is the fourth image thereof;

FIG. 5 is the fifth image thereof; and,

FIG. 6 is the sixth image thereof.

The broken lines in the drawings show a display screen or portionthereof and portions of the transitional graphical user interface thatform no part of the claimed design.

The appearance of the transitional image sequentially transitionsbetween the images shown in FIGS. 1-6. The process or period in whichone image transitions to another image forms no part of the claimeddesign.

CLAIM The ornamental design for a display screen or portion thereof withtransitional graphical user interface, as shown and described.